/Engine/Source/Runtime/Analytics/Analytics/Public/AnalyticsPropertyStore.h
Updates an exiting value. The operation is atomic from the caller perspective. The function reads the actual value and invoke UpdateFn callback with the actual value. The callback can update the actual value or decline the operation. If the key is not found, the callback is not invoked.
One of the following code
virtual [EStatusCode](API\Runtime\Analytics\Interfaces\IAnalyticsPropertyStore\EStatusCode) Update ( const [FString](API\Runtime\Core\Containers\FString) & Key, const [TFunction](API\Runtime\Core\GenericPlatform\TFunction)< bool(int32 &)> & UpdateFn )